In perforation of oil well casing at depths corresponding to the location of oil bearing formations, reusable guns have been used of the type illustrated and described in U.S. Pat. No. 3,565,188 to John R. Hakala. Expendable guns have also been utilized which are generally of the type shown in U.S. Pat. No. 3,739,723 to John R. Hakala. The present invention involves the use of expendable guns and, more particularly, to a perforating gun structure involving two or more guns for multiphase perforations, i.e., perforations at a given level in two or more controlled direction relationships.